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IMPROVEMENT IN SLIDE VALVES.

W. B. ROBINSON, OF DETROIT, MICHIGAN. Letters Patent No. 60,252, dated December 4, 1866.

SPECIFICATION. T() ALL WHOM IT MAY CONCERN:

Be it known that I, W, B. RQBINSON, of Detroit, in the county of Wayne, and Statc'of Michigan, have invented a new and improved Steam Valve; and I do hereby declare that tho following is a full, clear, and exact description thereof, which will enable others skilled in the art'to make and use the same, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure 1 represents a longitudinal vertical section of this invention.

Figure 2 is a horizontal section of the same.

Similar letters of reference indicate like parts.

This invention consists in a eounterbalance in combination with exhaust-passages in the valves in such ra manner that the exhaust steam is passed in a direct course lthrough the valve, eounterbalance, and steamchest cover; and furthermore, the cost oi' the valve and the engine is reduced, and steam is economzedrby shortening the ports in the cylinder to' the thickness of said cylinder 'or of the valve-seat.

A-represents avalve-chest, which communicates with the cylinder, B, through ports, a a', situated closeI t'o the ends of said cylinder, and passing straight through that side of the same which forms the seat for-the valves,

. C C'. These two valves are connected by the arched bridge, D, and they are at such distance apart, 'that when2 Vthe valve, C', covers the port, a', the port, a, is open, and vice versa. From the brldge, D, rises the icountei` balance, E, which is composed of a. cylindrical projection, provided at its top edge -with suitable packing rings, which work steam tight against the inner surface of the steam-chest' cover. The superiicial arca of the counterha'l` ance is so regulated that the valve is as near as possible balanced,land thatthe same works with the least pos-sible friction. The eshaust steam passes of through a4 channel, b, in tho interior of the bridge, D, and through the interior of thecylin'drical projection, E, in a' more direct course than in ordinary steam engines, thus rendering the exhaust free and relieving the piston of all back pressure.

By this arrangement the construction of the .steam cylinderris considerably simplified, the friction surface of the steam valve is reduced, and steam is economiz'ed by shortening the steam ports in steam cylinder to the thickness of cylinder and valve face. Y f

What I claim as new, and desire to secure by Letters Patent, is

The combination of the counterbalance E, having suitable packing rings, and the bridge D, with its passage b and valve C C', arranged with the valve chest A, and cylinder B, provided with port a a', and operating substantially as described for the purpose specified.

WILLIAM B. ROBINSON.

Witnesses:

Jsrrsnson WILEY, HENRY C. PENNY, 

